麻豆淫院

The fabrics that fill our homes, from natural cotton towels and bedsheets, to clothes produced with synthetic materials, produce microscopic fibers as they break down over time. Previous research has shown that household washers collect and release these microfibers into the environment, and now a new study uses citizen science to demonstrate how dryer vents also produce microfibers under normal household use.

The research, in Environmental Toxicology and Chemistry, estimates that household dryers are releasing more than 3,500 metric tons of microfibers each year in the U.S. alone (about 30 times the weight of the Statue of Liberty).

DRI scientists partnered with the environmental nonprofit Keep Tahoe Blue to recruit volunteers from the Lake Tahoe region for the study. Volunteers installed a mesh catchment system on the outside of their home dryer vents for three weeks and reported information on the materials in each dryer load. The results demonstrated that household dryers are significant sources of both naturally-derived (for example, cotton) and synthetic microfibers, both of which can carry the chemicals and dyes used to treat them into the environment.

"This study expands our understanding of how textiles are breaking down under typical household conditions," said Monica Arienzo, Director of DRI's Microplastics and Environmental Chemistry Lab and lead author of the research. "Because of the ubiquity of microfibers and their ability to contribute other chemicals to the environment, it's important for us to understand ways to reduce microfibers at the source. Household dryers could be one simple place to address them."

Synthetic fabrics like polyester, nylon, and spandex break down into microplastics over time, and made up more than half of global fabric production in 2023. Both synthetic and natural fibers like cotton, wool, and silk can be treated with dyes, flame retardants, PFAS chemicals for water repellency, and formaldehyde for wrinkle-free fabrics. Scientists are still in the beginning stages of investigating the environmental and human health impacts of these chemicals, which .

The washing and drying processes both produce microfibers, with washers introducing them into wastewater and dryers releasing them into the air. Most dryers in the U.S. are tumble dryers that vent hot air outside the building, and have no filter to catch microfibers after the lint filter. Other dryer types, such as condenser and heat pump dryers, are more common outside of the U.S. and may have different emissions.

Six volunteers installed mesh covers over their dryer vents for the research. They submitted relevant information about the materials being dried through the Citizen Science Tahoe smartphone app, which includes a range of other citizen science projects that allow the public to contribute to environmental research in the Lake Tahoe region.

The volunteers mailed the mesh covers back to DRI for analysis, where Arienzo and her team recorded the full weight of each and then analyzed their chemical compositions. A total of 76 dryer loads were recorded during the study period, with another 38 recorded for households that did not install the mesh covers. For each dryer load, the two largest items and their materials were reported, with towels, pants, and sheets as the most common and largest items.

The most common materials reported were cotton and polyester or fleece. Microfibers from natural fibers like cotton were more prevalent on the dryer vent mesh covers than those from synthetic fibers.

The amount of microfiber material on each dryer mesh varied widely, which is likely the result of variations in dryer model, age, and fabric condition. With more than 82 million electric dryers in the U.S. and the reported dryer use from the study volunteers, the researchers estimate that 3,543 metric tons of microfibers are released each year nationwide. Based on their analysis of the dryer vent mesh covers, they estimate that 2,728 metric tons are from natural fabrics while 460 metric tons are from synthetic fabrics.

"This volunteer-fueled research adds to our knowledge of pollution sources, like dryer vents, which can impact the ecosystems we cherish and depend on," said Marilee Movius, Sustainable Recreation Manager for Keep Tahoe Blue. "It also shows us how small behavioral changes鈥攕uch as installing more efficient lint filters or air-drying our clothes鈥攃an reduce microfiber emissions and protect the natural environment, Lake Tahoe, and ourselves."